Some science questions are urgent

1. The evidence for the origin of the universe is ( ).

a Hubble's Law.

2. The big ** theory holds that the universe was born from ( ).

d 15 billion years ago.

3. The theory of the origin of the universe, which is not supported by science, is that ( ) c The universe was created in the past quite recently, and in the seventeenth century Bishop Huchel calculated that the date of the birth of the universe was 4004 B.C.

4. According to the observations of scientists, the universe originated from ( ).

c Large**.

5. The following statement is correct (

a Light-years are units of distance.

6. The "heliocentric theory" eventually defeated the "geocentric theory", and this historical development process shows that ( )d people's understanding of the world has limitations and needs to be continuously developed and deepened.7 The following statements are correct (

b The distance between the Earth and the Sun is called an astronomical unit.

8. The following statement is incorrect ( ).

c The Milky Way is 20 billion years old.

9. The following statement is not a common feature of the motion of the planets in the solar system, but ( )d The orbit of the planet around the sun is on a sphere centered on the sun.10 The following statement is correct ( ).

a There are eight planets in the solar system.

Too much ho ho ho ho ho 1 !!

It's so hard to fight!! Hehe!

Light-years refers to the distance traveled in a year at the speed of light).

6d 7a8b 9d

10a Don't just look at the size of the grade, I only signed up a minute ago)

The volume of seawater that is discharged when a mine is submerged in water.

v row = v = then the buoyancy experienced by the submerged in the water.

F float = p seawater v discharge g = 1020kg m *

Because the f float is greater than g

So float up and eventually float on the water.

If you want to remove a small amount of sulfuric acid mixed with dilute nitric acid to obtain pure dilute nitric acid, you should add an appropriate amount of Ba(NO3)2 solution The chemical equation for the reaction is Ba(NO3)2+H2SO4=BASO4 +2HNO3

If you want to remove a small amount of hydrochloric acid mixed in the sodium chloride solution to obtain a pure sodium chloride solution, you should add an appropriate amount of Na2CO3 solution The chemical equation in which the reaction occurs Na2CO3+2HCl=2NaCl+H2O+CO2 The type of reaction is Metathesis reaction

1.Common strong acids are (sulfuric acid).(Nitric acid).(hydrochloric acid), etc.; Common weak acids are (carbonic acid) and so on.

2.Litmus test solution, which can identify the (acid-base) properties of the solution.

3..pH test paper can not only identify the acidity and alkalinity of the solution, but also the acidity and alkalinity (degree) of the solution

4.Acids can react with certain salts to form new acids and salts.

For example: H2SO4 + BA(NO3)2---BASO4+2HNO3).

5.Acids can react with certain metal oxides to form (corresponding metal salts) and (water).

For example: cuo + hcl --cucl2+h2o).

6.Acids can react with certain metals to form (corresponding metal salts) and (hydrogen).

For example: zn + h2so4 --znso4 + h2).

7.Dilute sulfuric acid is often used to remove rust, and in the process of rust removal, gas is generated. Please use two equations to explain, 3H2SO4+FE2O3==FE2(SO4)3+3H2O)).

fe+h2so4==feso4+h2）

1 Hno3 H2SO4 H2CO3 2 Acidity and alkalinity 3 Degree (this is so tangled) 4 Nitric acid and barium sulfate (precipitate) 5 Water and salt H2O CuCl2

6 Gases and salts: Hydrogen and zinc sulfate.

7 Hydrolysis of iron ions to iron hydroxide and hydrogen ions The equation for sulfuric acid and hydrogen ions to produce hydrogen was written by myself.

1 NaOH koh Ba(OH)2 H2CO32 Acidity and alkalinity.

3 Strength and weakness. 4 BaSO4 precipitates +2Hno3

5 Salt and water CuCl2+H2O

6 Salt and hydrogen ZNSO4+H2

7 fe2o3 +3h2so4=fe2(so4)3 +3h2ofe+h2so4=feso4+h2

1. Hydrochloric acid, nitric acid, sulfuric acid, carbonic acid.

2. Acid and alkali. 3. Concentration.

4、baso4↓+2hno3

5. Salt water Cuo + 2HCl====CuCl2 + H2O6, salt hydrogen ZnSO4 + H2

7、fe2o3 + 3h2so4===fe2(so4)3 + 3h2o

fe + h2so4 ***** feso4 + h2↑

Artificial incubation technology is not new.

Tell you a mantra that is upside down and left and right in reverse. So when you see the east and west moving to the lower right in the field of view, it is actually moving in the upper left direction, so you should move the slide in the d direction so that the microorganism does not disappear from the field of view.

In short, where the image of Liangshan Chang moves, the slide also moves.

The owner of the A building didn't learn the bridge well, and the first question was sharp, and the direction in the microscope was reversed, up is down, down is up, left is right, right is left!